CSS: box-sizing: content-box vs border-box

Sources: http://www.w3schools.com/cssref/css3_pr_box-sizing.asp | https://css-tricks.com/box-sizing/ | http://www.binvisions.com/articles/box-sizing-property-difference-content-border/

Box-sizing

• content-box
• Default. 
• Width or height = content's width or height. Border, padding, or margin are not included

• border-box
• Width or height = content + padding + border width or height. Margin is not included.

• initial
• Sets this property to its default value.
• inherit
• Inherits this property from its parent element.